Question

A M30 bolt needs to be subjected to pretension \( F_1 = 350 \, \text{kN} \). If the torque coefficient \( K \) of the bolt is 0.2, then the torque in Nm needed to achieve this pretension is _________.
\text{[in integer]}

Hint:

To calculate the torque needed to achieve a pretension, use the formula \( T = K F_1 d \), where \( d \) is the diameter of the bolt.

Answer 1

Correct Answer: 2100

The torque needed to achieve the pretension is given by the formula: \[ T = K F_1 d, \] where:
- \( K = 0.2 \) (torque coefficient),
- \( F_1 = 350 \, \text{kN} = 350 \times 10^3 \, \text{N} \),
- \( d = 30 \, \text{mm} = 0.03 \, \text{m} \) (diameter of the bolt).
Substituting the values: \[ T = 0.2 \times 350 \times 10^3 \times 0.03 = 2100 \, \text{Nm}. \] Thus, the torque needed is 2100 Nm.